I have a Big Blue brand dive light (that doesn’t have model number listed on it), which runs off this 3xAAA battery insert. The insert measures 22mm dia x 60mm length (though the positive end button compresses down to 56mm length). Is there a li ion battery that I can replace this with? I tried an 18500 and it is too short, and an 18650 is too long.
by Zpearo
2 Comments
3xAAA would require 3×10440 as replacements but there’s every possibility that light will die on 3.7v. Your best bet is probably lithium AAAs or rechargeable AAAs.
Many (though not all) lights with a 3xAAA carrier can take a sleeved 18650. Some even have that listed as an option, and may even include the sleeve.
However, as you have already tried 18500 (too short) and 18650 (too long), I’m thinking your only option is 18500 with spacers. I have no idea now thick [Simon’s spacers](https://convoylight.com/products/pcb-board-spacer-for-battery-for-series-connection-increase-the-length-to-fill-the-gap?data_from=app_searchbox&variant_sku_code=5086261-4961529-24174792-8617549-40831260-0-0) are, but I think one on each end may get you close enough.